Pumping system

ABSTRACT

A pair of pumps each has an outlet connectable with a different user. A regulating unit regulates the outputs of the pumps at their outlets and includes a housing having two spaced pressure chambers each communicating with one of the outlets, a communicating bore which connects the chambers, a hollow regulating sleeve which is slidably accommodated in the bore and connected with the pumps so that as it slides it will regulate the operation of the same, and a piston located in the sleeve. One axial annular end of the sleeve is exposed to the pressure of fluid in one of the chambers and an axial end face in the region of the other axial end of the sleeve is exposed to the pressure of fluid in the other of the chambers. A spring biases the sleeve in one axial direction.

Unite States atent 1 1 Bosch 1 Mar. 4, 1975 PUMPING SYSTEM [75] Inventor:

22 Filed: Feb. 8, 1973 [21] Appl. No.: 330,514

Paul Bosch, Ludwigsburg, Germany [30] Foreign Application Priority Data Apr. 7, 1972 Germany 2216680 [52] US. Cl. 417/212 [51] Int. Cl. F04b 49/00 [58] Field of Search 417/216, 286,212

[56] References Cited UNITED STATES PATENTS 3,723,026 3/1973 Soyland 417/216 FOREIGN PATENTS OR APPLICATIONS 1,212,609 11/1970 Great Britain 417/216 1,922,269 11/1970 Germany 417/216 1,453,586 4/1969 Germany 417/216 Primary Examiner-William L. Freeh Assistant E.\'aminer-Gregory Paul La Pointe Attorney, Agent, or FirmMichael S. Striker [57] ABSTRACT A pair of pumps each has an outlet connectable with a different user. A regulating unit regulates the outputs of the pumps at their outlets and includes a housing having two spaced pressure chambers each communieating with one of the outlets, a communicating bore which connects the chambers, a hollow regulating sleeve which is slidably accommodated in the bore and connected with the pumps so that as it slides it will regulate the operation of the same, and a piston located in the sleeve. One axial annular end of the sleeve is exposed to the pressure of fluid in one of the chambers and an axial end face in the region of the other axial end of the sleeve is exposed to the pressure of fluid in the other of the chambers. A spring biases the sleeve in one axial direction.

6 Claims, 1 Drawing Figure PUMPING SYSTEM BACKGROUND OF THE INVENTION The present invention relates to a pumping system in general, and more particularly to a pumping system using two coupled pumps each of which supplies a separate user circuit.

The use of two pumps which are coupled so as to operate in unison and which each supply a separate user circuit, is already known. It is also known to provide an arrangement for regulating the operation of the two pumps by means of a movable component associated with a regulating device of the system. It is known from German Pat. No. 1,453,586 to provide such an arrangement wherein the regulating unit has stepped piston which is slidable in a correspondingly stepped bore. Each step is associated with one of the user circuits. Unfortunately, this arrangement has certain structural features which tend to block the piston against sliding movement unless the various components are manufactured and installed so as to have precisely defined relative relationships. This, however, requires manufacturing of the components to very precise tolerances, which is expensive and therefore undesirable.

Another suggestion has been to use separate individual pistons, each controlled by one of the user circuits, instead of the stepped piston mentioned above, or to use separate adjusting devices in parallel. This of course means a complex construction and, in consequence, considerable expense in the manufacture and sale of such units.

SUMMARY OF THE INVENTION The general object of the invention is to overcome the disadvantages of the prior art.

More particularly it is the object of the present invention to provide a pumping system of the type outlined above, and in particular a regulating system in the pumping system which is simple in construction and therefore inexpensive to produce.

Another object of the invention is to provide, in such a pumping system, a regulating unit of the type under discussion which does not require that its constituent components be manufactured to precise tolerances.

In keeping with these objects, and with others which will become apparent hereafter, one feature of the invention resides in a pumping system, in a combination which comprises a pair of pumps each having an outlet connected with a different user, and a regulating unit for regulating the output of the pumps. The regulating unit comprises a housing having two spaced pressure chambers each communicating with one of the outlets, a connecting bore connecting the chambers, a hollow regulating sleeve slidably accommodated in this bore in operative association with the pumps for regulating the same and having one annular end face exposed to the pressure in one of the chambers, a piston extending into the sleeve inwardly of the other annular end face of the same and having an axial end face exposed to the pressure in the other of the chambers, and a spring biasing the sleeve in one axial direction of the same.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation together with additional objects and advantages thereof will best be understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is a partly sectional, partly diagrammatic view illustrating an embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing in detail, it will be seen that in the exemplary embodiment which has been illustrated', reference numeral 10 identifies a housing of a regulating unit for the two pumps 24 and 27. The housing is provided with a blind bore 11 in which a piston 12 is in part accommodated so that it has play, meaning that it can move transversely of its elongation and can also perform limited skewing movements. The blind bore 11 merges into a housing bore 13 which is concentric with it and which in turn merges into a cylindrical chamber 14. A hollow sleeve is provided with a second blind bore 15 and in part surrounds the piston 12, the sleeve being slidably axially thereon in sealing engagement with it. Sleeve 15 has an enlarged portion 17 which extends into the cylindrical chamber 14 and defines at its juncture with the remainder of the sleeve a shoulder 17 which serves as an abutment determinative of the extent to which the sleeve 16 can move into the bore 13.

The cover 18 is provided on the housing 10, closing the same, and being abutted by the ends of two springs 19, 20 the opposite ends of which abut the enlarged portion 17 of the sleeve 16. A pin, bolt or other member 21 is fast with the portion 17 and is embraced in a slot of a bifurcated lever 22 which is thus pivotable about it. The lever 22 in turn is connected with an adjusting element 23 that is also connected with the pump 24, and in addition it is connected via a linkage 25 with an adjusting element 26 of the pump 27. This means that when the lever 23 moves, both of the pumps 24 and 27 will be adjusted in the same sense and to the same extent. The two pumps are coupled with one another and are jointly driven by a drive 28, and the output of the pump 24 is connected with a user circuit 30 leading to a non-illustrated first user, whereas the output of the pump 27 is connected with a circuit 31 leading to a non-illustrated second user which is different and separate from the first user.

The housing is provided with a bore 33 which communicates via a conduit 32 with the user circuit 30 and which also communicates with the bore 13 adjacent the end of the same which merges into the blind bore 11. A further bore in the housing 35 communicates with an annular space 36 surrounding the inner wall bounding the bore 13, adjacent the end which merges into the cylindrical chamber 14. In addition, the bore 35 communicates via a conduit 34 with the user circuit 31.

The circumferential wall of the sleeve 16 is provided with a plurality of radial bores 37 located in the region of the inner end of the blind bore 15, and in addition with further radial bores 38 of substantially smaller diameter than that of the bores 37 and which are located in one or several transverse planes of the sleeve 16.

The sealing ring 39 is provided on the end portion of the piston 12 which is located in the blind bore 11 and the latter is connected via a bore 40 with a reservoir 41. Reference numeral 42 designates a fluid reservoir from which fluid is drawn by the suction side of the two pumps 24 and 27. The axial annular end face F1 on the sleeve 16 and the circular axial end face F2 corresponding to the diameter of the piston 12, are proportional to the throughput capacities of the pump 24 and 27, respectively.

It will be appreciated that the pumps 24 and 27 are driven at the identical speed by the drive 28 because they are mechanically coupled for this purpose. When the pumps are so driven, then the members 23 and 26 will originally assume positions in which the pumps provide their maximum output into the user circuit. If subsequently the resistance to the fluid flow increases in one or both of the circuits 30, 31 (due to the operation of the associated user), then the resulting back pressure is communicated via the conduits 32, 34 into the pressure chambers 43, 44 of which the former communicates with the surface F1 and the latter with the surface F2. This means that the sleeve 16 is subjected to the pressure of the fluid in the respective user circuits at two spaced locations. As a result, the sleeve 16 is displaced axially counter to the force of the springs 19, and in so doing causes the lever 26 to move and via the same and the linkages associated with the lever to regulate the setting of the pumps by exactly the same amount by which it has been axially displaced. In other words, the force acting upon the sleeve 16 is proportional to the sum of the outputs of the two pumps 24, 27. The fluid pressure in the circuit 30 acts in the pressure chamber 43 and the fluid pressure in the user circuit 31 acts via conduit 34, bore 35 and annular groove 36 in the pressure chamber 34 which is located in the interior of the sleeve 16.

It is desirable that the construction be small, which includes, inter alia, that the springs 19, 20 be small. To make this possible the surfaces F1 and F2 must be relatively small, and this in turn permits the wall thickness of the sleeve 16 to be correspondingly thin. In order to avoid deformation and hydraulic jamming of the member 16 to the maximum possible extent, the pressures acting at its interior and at its exterior at radially opposite locations must be identical, which is achieved by the fact that the sealing distances inside and outside are identical and by the radial bores 38 which permit pressure fluid leaking from the chambers 43 or 44 to escape.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a pumping system, it is not intended to be limited to the details shown, since various modifications and structural changes can be made without departing in any way from the spirit and concept of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others by applying current knowledge can readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

What is claimed is:

1. In a pumping system, a combination comprising a pair of pumps each having an outlet connectable with a different user; and a regulating unit for regulating the output of said pumps, comprising a housing having a first bore, a hollow regulating sleeve slidably accommodated in said first bore in operative association with said pumps for regulating the same and having one annular end face in part bounding a first pressure chamber, a piston accommodated in a second bore in said sleeve inwardly of the other annular end face of the same and having an axial end face in part bounding a second pressure chamber in said second bore, and a spring biasing said sleeve in one axial direction of the same, each of said pressure chambers communicating with a different one of said outlets.

2. A combination as defined in claim 1, said second bore being a blind bore concentric with said connecting bore, and said piston being located at least partly with play in said blind bore.

3. A combination as defined in claim 1, said pumps being regulatable between a maximum output condition and a lesser output condition; and further comprising abutment means for stopping the sliding movement of said sleeve in a position in which said sleeve regulates said pumps to assume said maximum output condition.

4. A combination as defined in claim 3, wherein said abutment means comprises a shoulder provided on said sleeve.

5. A combination as defined in claim 1, and further comprising a lever pivoted to said sleeve, and a rod linkage connected with said lever and said pumps for regulating the latter in response to pivoting of said lever as a result of sliding displacement of said sleeve.

6. A combination as defined in claim 1, wherein said sleeve is provided with at least one aperture in its peripheral wall, said aperture communicating with said second chamber. 

1. In a pumping system, a combination comprising a pair of pumps each having an outlet connectable with a different user; and a regulating unit for regulating the output of said pumps, comprising a housing having a first bore, a hollow regulating sleeve slidably accommodated in said first bore in operative association with said pumps for regulating the same and having one annular end face in part bounding a first pressure chamber, a piston accommodated in a second bore in said sleeve inwardly of the other annular end face of the same and having an axial end face in part bounding a second pressure chambeR in said second bore, and a spring biasing said sleeve in one axial direction of the same, each of said pressure chambers communicating with a different one of said outlets.
 2. A combination as defined in claim 1, said second bore being a blind bore concentric with said connecting bore, and said piston being located at least partly with play in said blind bore.
 3. A combination as defined in claim 1, said pumps being regulatable between a maximum output condition and a lesser output condition; and further comprising abutment means for stopping the sliding movement of said sleeve in a position in which said sleeve regulates said pumps to assume said maximum output condition.
 4. A combination as defined in claim 3, wherein said abutment means comprises a shoulder provided on said sleeve.
 5. A combination as defined in claim 1, and further comprising a lever pivoted to said sleeve, and a rod-linkage connected with said lever and said pumps for regulating the latter in response to pivoting of said lever as a result of sliding displacement of said sleeve.
 6. A combination as defined in claim 1, wherein said sleeve is provided with at least one aperture in its peripheral wall, said aperture communicating with said second chamber. 